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SUMMARY / RELATED TOPICS

Photoresistor

A photoresistor is an active component that decreases resistance with respect to receiving luminosity on the component's sensitive surface. The resistance of a photoresistor decreases with increase in incident light intensity. A photoresistor can be applied in light-sensitive detector circuits and light-activated and dark-activated switching circuits acting as a resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megaohms, while in the light, a photoresistor can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band; the resulting free electrons conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can differ among dissimilar devices. Moreover, unique photoresistors may react differently to photons within certain wavelength bands. A photoelectric device can be either extrinsic.

An intrinsic semiconductor has its own charge carriers and is not an efficient semiconductor, for example, silicon. In intrinsic devices, the only available electrons are in the valence band, hence the photon must have enough energy to excite the electron across the entire bandgap. Extrinsic devices have impurities called dopants, added whose ground state energy is closer to the conduction band. If a sample of silicon has some of its atoms replaced by phosphorus atoms, there will be extra electrons available for conduction; this is an example of an extrinsic semiconductor. Photoresistors are less light-sensitive devices than photodiodes or phototransistors: the two latter components are true semiconductor devices, while a photoresistor is an active component that does not have a PN-junction; the photoresistivity of any photoresistor may vary depending on ambient temperature, making them unsuitable for applications requiring precise measurement of or sensitivity to light photons. Photoresistors exhibit a certain degree of latency between exposure to light and the subsequent decrease in resistance around 10 milliseconds.

The lag time when going from lit to dark environments is greater as long as one second. This property makes them unsuitable for sensing flashing lights, but is sometimes used to smooth the response of audio signal compression. Photoresistors come in many types. Inexpensive cadmium sulfide cells can be found in many consumer items such as camera light meters, clock radios, alarm devices, outdoor clocks, solar street lamps and solar road studs, etc. Photoresistors can be placed in streetlights to control. Ambient light falling on the photoresistor causes the streetlight to turn off, thus energy is saved by ensuring. They are used in some dynamic compressors together with a small incandescent or neon lamp, or light-emitting diode to control gain reduction. A common usage of this application can be found in many guitar amplifiers that incorporate an onboard tremolo effect, as the oscillating light patterns control the level of signal running through the amp circuit; the use of CdS and CdSe photoresistors is restricted in Europe due to the RoHS ban on cadmium.

Lead sulfide and indium antimonide LDRs are used for the mid-infrared spectral region. Ge:Cu photoconductors are among the best far-infrared detectors available, are used for infrared astronomy and infrared spectroscopy. Optoelectronics Photodetector Using a photoresistor to track light Connecting a photoresistor to a circuit Photoresistor overview - detailing operation and circuit information

Aero, British Columbia

Aero or Aero Camp was a logging camp and associated post office on Moresby Island in Haida Gwaii off the North Coast of British Columbia, Canada. It was founded in 1933 by the A. P. Allison Logging Company, known as Allison Camp. In 1936, a logging railroad was constructed to give the beach-based camp access to inland timber. At the start of World War II, Aero Camp became a source of high quality Sitka spruce used to build aircraft, including the famous mosquito bomber. In 1942, at the height of the war, the camp was taken over by Aero Timber Products Ltd. At this point the camp's name was changed to Aero Camp; the Aero post office was designated on October 7, 1948, opened on October 23 of that year, closed on January 15, 1958. Aero was listed as a steamboat landing and appeared on the regular scheduled services of the Union Steamship Company of British Columbia in 1954, 1955 and 1957. From 1959 to 1964 the landing was served by Northland Navigation Company steamers. Logging had ceased by 1965 but a watchman remained on site and the wharf remained in use by fishing vessels.

BCGNIS listing "Aero"

Striated swallow

The striated swallow is a species of swallow found in open hilly areas and cultivation in South and Southeast Asia to northeastern India and Taiwan. The striated swallow was sometimes considered to a subspecies of red-rumped swallow; the striated swallow is 19 cm long with a forked tail. It streaked chestnut rump; the face and underparts are white with heavy dark streaking. The wing are brown; the sexes are alike but juveniles are duller and browner, with a paler rump and shorter outer tail feathers. There are The Philippines and Indonesia. C. s. mayri breeds from northeastern India to northeastern Bangladesh. It has broader streaks than nominate striolata. C. s. stanfordi breeds from northeastern Myanmar to northern Thailand. It has broad streaks. C. s. vernayi breeds locally in western Thailand. It is more rufous below than the nominate race, is only faintly streaked on the rump; the contact call is pin, the alarm is chi-chi-chi, the song is a soft twittering. This species subspecies mayri is similar to red-rumped swallow of the race japonicus, but is larger, more streaked, has a less distinct neck collar.

The island subspecies are resident, but the continental races mayri and stanfordi are partial migrants which move south in the winter. The striated swallow semi-colonially with scattered nests; the nest is a retort or bottle shaped structure, made from mud pellets and lined with dried grasses and feathers. The clutch is four, sometimes five, white eggs except for badia, where two eggs is normal. Both sexes build the nest, share incubation and the care of the young. Nests are constructed in natural caves, but often in artificial sites on bridges, in culverts and on buildings; the striated swallow feeds low at cliff faces on flying insects. It has a slow buoyant flight compared to barn swallow, it will feed with other swallow species. BirdLife International. "Hirundo striolata". IUCN Red List of Threatened Species. IUCN. 2004. Retrieved 6 May 2006.old-form url Turner, Angela K. Swallows & Martins: An Identification Guide and Handbook. Houghton Mifflin. ISBN 0-395-51174-7. Robson Birds of Thailand ISBN 1-84330-921-1

RAE Scarab

The RAE Scarab was a light single-engined single-seat parasol winged modification of the de Havilland Humming Bird, flying in the United Kingdom in 1932. Only one was built; the Aero Club of the Royal Aircraft Establishment built two light aircraft in 1923, the Zephyr and the Hurricane no more until 1931. This, their final effort was the RAE Scarab or PB Scarab as it is sometimes known, after its designers P G N Peters and C R Brewer. So, it was not all their own work for the wing and empennage were from a low-winged DH.53, itself a 1923 aircraft. What they did was to reposition the wing on a new fuselage to make a new, parasol winged monoplane, a change that required the creation of a centre section and the struts to support it. With its new fuselage, the Scarab was longer at 21 ft 0 in compared with 19 ft 8 in. Most of the extra length was in the nose, for the DH.53 was a snub-nosed machine compared with the Scarab. Both aircraft had flat sided fuselages built up from four longerons in the usual manner of the time, with rounded decking.

The DH.53 pilot had sat over mid-chord, but the combination of 5o of sweepback and the change of centre of gravity due to the longer nose in the Scarab meant he could sit at the trailing edge of the new, narrow chord centre section. Given the small gap between the top of the fuselage and the underside of the parasol wing, a mid chord cockpit would have been inaccessible and have restricted the pilot's view severely. A pair of lift stuts extended in a V from the lower fuselage longerons on each side to the two wing spars at the point where these were thickened for the compression struts of the DH.53. As on the DH.53, the wings had constant chord with rounded tips, carrying long differential ailerons. In contrast to those of the DH.53, the wings of the Scarab folded for transport. The Scarab's undercarriage was new, a split axle unit with the main legs going to the upper longerons and bracing to the lower ones; the undercarriage track was 5 ft. Like some DH.53s, the Scarab was powered by a 32 hp Bristol Cherub III flat twin.

The sole Scarab was registered as G-ABOH. Its first flight was in February 1932 with H. H. Leech at the controls. Though underpowered and slow, it had a surprising rate of climb, it flew from Farnborough until 1938, when it was stored and scrapped in 1945. Data from Flight 19 February 1932 p.149General characteristics Crew: 1 Length: 21 ft 0 in Wingspan: 30 ft 0 in Height: 6 ft 9 in Wing area: 127 sq ft swept Empty weight: 460 lb Gross weight: 650 lb Powerplant: 1 × Bristol Cherub III flat twin, 32 hp at 3,200 rpmPerformance Maximum speed: 78 mph Cruise speed: 68 mph Stall speed: 32 mph Range: 200 mi Rate of climb: 600 ft/min Jackson, A. J.. British Civil Aircraft 1919-59. 2. London: Putnam Publishing. Jackson, A. J.. British Civil Aircraft since 1919 Volume 3. London: Putnam. ISBN 0-370-10014-X. Jackson, A. J.. de Havilland Aircraft since 1909. London: Putnam Publishing. ISBN 0-370-30022-X. Ord-Hume, Arthur W. J. G.. British Light Aeroplanes. Peterborough: GMS Enterprises. ISBN 978-1-870384-76-6

Tjukurla Community

Tjukurla is a medium-sized Aboriginal community, located in the Goldfields-Esperance Region of Western Australia, within the Shire of Ngaanyatjarraku. In the early 1980s a bore was put down near the present Tjukurla Community as part of the outstation movement from Docker River community. In mid 1981 an outstation was established at Kintore which provided an opportunity for those living at Papunya to move west, closer to their traditional lands. From Kintore many people moved to Tjukurla. Residents came from Warakurna, Docker River and a few from Warburton; the community is located within the Determined Ngaanyatjarra Lands Native Title claim area. The community is managed through its incorporated body, Tjukurla Community Aboriginal Corporation, incorporated under the Aboriginal Councils and Associations Act 1976 on 17 February 1987. Tjukurla Layout Plan No.1 has been prepared in accordance with State Planning Policy 3.2 Aboriginal Settlements. Layout Plan No.1 is yet to be endorsed by the community.

Office of the Registrar of Indigenous Corporations Native Title Claimant application summary

Guam flycatcher

The Guam flycatcher, or Guam broadbill, is an extinct species of bird in the family Monarchidae endemic to Guam. Some authorities consider the Guam flycatcher to have been a subspecies of the Oceanic flycatcher. Alternate names for the Guam flycatcher include Guam Myiagra, Guam Myiagra flycatcher, Marianne Islands flycatcher, Marianne Islands Myiagra flycatcher, Micronesian broadbill and Micronesian Myiagra; the Guam flycatcher was a small bird measuring 5 inches long with different coloration for the males and females. Males were glossy blue-black above. Both had white below and buff coloration on the breast, it had a wide bill with long "whiskers". The bird was secretive and occurred in limestone and ravine forests. Although common on Guam as as the early 1970s, the flycatcher's population went into a rapid decline due to predation by the brown tree snake, Boiga irregulars, accidentally introduced to the island in the 1940s; the last sighting of the flycatcher occurred in the Santa Rosa area in 1983.

Given the small size of the island, the complete absence of recent sightings, the universal presence of the brown tree snake in the bird's former habitat, the Guam flycatcher is considered extinct